When I was around 14 or so, I fell asleep while reading a book at the beach. I was lying on my stomach so the entire back of my legs took the brunt of it. I was fried - bright red and extremely painful. I started to blister slightly and my grandfather told me to put white vinegar on the backs of my legs and it would feel better.
I always listened to my grandpa so I went in the bathtub and poured white vinegar down the back of both my legs. Well, let me tell you one thing he forgot to mention...that hurt like the dickens! I did some screeching, believe me.
But you know what? Once the initial sting died down, I felt a lot better. It took the heat from the sunburn and made the blisters go away completely. I didn't even peel after and I always peeled after sunburn.